Special serializers for script which detect common cases and encode
them much more efficiently. 3 special cases are defined:
* Pay to pubkey hash (encoded as 21 bytes)
* Pay to script hash (encoded as 21 bytes)
* Pay to pubkey starting with 0x02, 0x03 or 0x04 (encoded as 33 bytes)
Other scripts up to 121 bytes require 1 byte + script length. Above
that, scripts up to 16505 bytes require 2 bytes + script length.
This introduces internal types:
* CKeyID: reference (hash160) of a key
* CScriptID: reference (hash160) of a script
* CTxDestination: a boost::variant of the former two
CBitcoinAddress is retrofitted to be a Base58 encoding of a
CTxDestination. This allows all internal code to only use the
internal types, and only have RPC and GUI depend on the base58 code.
Furthermore, the header dependencies are a lot saner now. base58.h is
at the top (right below rpc and gui) instead of at the bottom. For the
rest: wallet -> script -> keystore -> key. Only keystore still requires
a forward declaration of CScript. Solving that would require splitting
script into two layers.
This commit removes the dependency of serialize.h on PROTOCOL_VERSION,
and makes this parameter required instead of implicit. This is much saner,
as it makes the places where changing a version number can have an
influence obvious.
This patch enabled compressed pubkeys when -compressedpubkeys is passed.
These are 33 bytes instead of 65, and require only marginally more CPU
power when verifying. Compressed pubkeys have a different corresponding
address, so it is determined at generation. When -compressedpubkeys is
given, all newly generated addresses will use a compressed key, while
older/other addresses keep using normal keys. Unpatched clients will
relay and verify these transactions.
Instead of conversion functions between pubkey/uint160/address in
base58.h, have a fully fledged class CBitcoinAddress (CAddress was
already taken) to represent addresses.
Pieter Wuille